Vane-type cam adjustors, sometimes referred to as phasers or actuators, are used conventionally to adjust the angular relationship between the camshaft and the internal combustion engine crankshaft. Such devices have a rotor housed within a stator and the rotor has vanes which radially extend into pressure chambers of the stator and divide the pressure chambers. A pressure medium is pumped onto one of the sides of the pressure chamber in order to shift the rotor relative to the stator. This shifting provides for an angular adjustment of the camshaft with respect to the crankshaft and adjustment of the timing for opening and closing of various valves which are affected by the camshaft.
In order to change the resultant sum of the moments acting on the device, springs are sometimes used. Coil springs, which are often used, are mounted in the center of the rotor, one end of the spring is fixed to the rotor and the other end of the spring is fixed to a cover of the stator by pins, bolts or a casting feature. Coil springs are not capable of withstanding a large number of load cycles with a high pre-torque. Coil springs also are difficult to use in engines with high camshaft friction.
Another type of spring that has been employed are flat, spiral torsion springs. Typically, these spiral torsion springs were fixed to the rotor and the stator by means of pins or screws. In some cases, it can be difficult to package these pins or screws. Thus, there is a need for alternative spring retainers for use with spiral torsion springs.